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    waltky's Avatar Senior Member
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    Lightbulb Astronomy & Cosmology

    Granny wonderin' how dey s'posed to find it if ya can't see it?...

    Quasars illustrate dark energy's roller coaster ride
    13 November 2012 - BOSS data is acquired by the 2.5m Sloan telescope at Apache Point Observatory in the US
    Scientists have used a novel technique to probe the nature of dark energy some 10 billion years into the past. They hope it will bring them closer to an explanation for the strange force that appears to be driving the Universe apart at an accelerating rate. The method relies on bright but distant objects known as quasars to map the spread of hydrogen gas clouds in space. The 3D distribution of these clouds can be used as a tracer for the influence of dark energy through time. A scholarly paper describing the approach has been submitted to the journal Astronomy & Astrophysics and posted on the arXiv.org preprint site. It is authored by the BOSS (Baryon Oscillation Spectroscopic Survey) team, which uses the 2.5m Sloan Foundation Telescope in New Mexico, US, to make its observations of the sky.

    The international group's new data is said to be a very neat fit with theory, confirming ideas that dark energy did not have a dominant role in the nascent Universe. Back then, gravity actually held sway, decelerating cosmic expansion. Only later did dark energy come to the fore. "We know very little about dark energy but one of our ideas is that it is a property of space itself - when you have more space, you have more energy," explained Dr Matthew Pieri, a BOSS team-member. "So, dark energy is something that increases with time. As the Universe expands, it gives us more space and therefore more energy, and at some point dark energy takes over from gravity to end the deceleration and drive an acceleration," the Portsmouth University, UK, researcher told BBC News.


    The BOSS team used 48,000 distant quasars to "back-light" and map the distribution of clouds of hydrogen gas in the early Universe

    The discovery that everything in the cosmos is now moving apart at a faster and faster rate was one of the major breakthroughs of the 20th Century. But scientists have found themselves grasping for new physics to try to explain this extraordinary phenomenon. A number of techniques are being deployed to try to get some insight. One concerns so-called baryon acoustic oscillations. These refer to the pressure-driven waves that passed through the post-Big-Bang Universe and which subsequently became frozen into the distribution of matter once it had cooled to a sufficient level. Today, those oscillations show themselves as a "preferred scale" in the spread of galaxies - a slight excess in the numbers of such objects with separations of 500 million light-years.

    It is an observation that can be used as a kind of standard ruler to measure the geometry of the cosmos. The BOSS team has already done this using a large volume of galaxies that stretch some six billion light-years from Earth. But at greater distances - and hence deeper in cosmic time - these standard galaxies are simply too faint for the Sloan telescope to see. Instead, the BOSS team has used quasars (quasi-stellar radio sources) to help it map the cosmos. Quasars are far flung galaxies where a massive central black hole is driving the emission of huge amounts of electromagnetic radiation. These are visible to Sloan.

    More http://www.bbc.co.uk/news/science-environment-20303592

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    Chris (11-19-2012)

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    DonGlock26's Avatar Senior Member
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    Amazing.

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    Lightbulb

    Hubble spots dark vortex on Neptune...

    Hubble locates new dark spot on Neptune
    June 23, 2016 - The last several Neptune vortices seen by astronomers have exhibited a wide range of sizes and shapes.
    There's a new dark spot on Neptune, the farthest planet from the sun. Astronomers recently confirmed the presence of a dark vortex spinning across the planet's atmosphere after examining imagery collected by the Hubble Space Telescope last month. It's the first Neptune vortex discovered since 1994.

    The high pressure system is accompanied by bright companion clouds. Researchers believe the clouds are formed as the vortex pushes ambient air higher into the atmosphere, forcing gases to freeze into methane ice crystals. "Dark vortices coast through the atmosphere like huge, lens-shaped gaseous mountains," Mike Wong, a researcher astronomer at the University of California, Berkeley, said in a news release. "And the companion clouds are similar to so-called orographic clouds that appear as pancake-shaped features lingering over mountains on Earth."


    Wong led the investigation of Hubble data that yielded the discovery of the new dark spot. Jupiter hosts similar cyclone-like disturbances, but the gas giant's vortices are more uniform and sometimes persist, slowly evolving, for decades. Previous studies have proven Neptune's vortices to be a permanent feature, but the disturbances are shorter-lived.

    The last several Neptune vortices seen by astronomers have exhibited a wide range of sizes and shapes, and have proven to be relatively unstable -- wandering north and south, speeding up and slowing down. Scientists hope further monitoring of Neptune's vortices will illuminate how they originate and the factors that influence their fluctuations.

    http://www.upi.com/Science_News/2016...?spt=sec&or=sn
    See also:

    ‘Dark Vortex’ Spotted on Neptune
    June 24, 2016 - The vortex is about the same size as the US
    Astronomers have spotted a “dark vortex” swirling in Neptune’s atmosphere. Using high resolution images captured in May by the Hubble Space Telescope, researchers say the vortex is about the size of the continental United States.

    The vortex is a high pressure system and is accompanied by bright clouds. In 2015, astronomers spotted clouds and later a dark spot nearby. The May 2016 images confirmed the presence of the vortex. "Dark vortices coast through the atmosphere like huge, lens-shaped gaseous mountains," said University of California at Berkeley research astronomer Mike Wong. "And the companion clouds are similar to so-called orographic clouds that appear as pancake-shaped features lingering over mountains on Earth." Vortices on Neptune have been spotted before. In 1989, the Voyager 2 spacecraft saw one, and in 1994, Hubble pinpointed one.


    A dark vortex was spotted on Neptune.

    Astronomers say the vortices “have exhibited surprising diversity over the years, in terms of size, shape, and stability (they meander in latitude, and sometimes speed up or slow down).” They also have relatively short lifespans compared to anticyclones seen on Jupiter, which “evolve over decades. Further study should yield a better understanding about how vortices develop, what causes them to move and how they interact with the environment, researchers said. Neptune is roughly 4.3 billion kilometers from the Sun, and it takes 165 Earth years to make one orbit of the sun.

    http://www.voanews.com/content/mht-d...e/3390910.html

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    Crepitus's Avatar Senior Member
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    Cool info, but as a member of "Friends of Pluto" I must take exception to calling Neptune the farthest planet.
    Ever notice how most people are like Slinkies? They're really kinda useless but they still make you smile when you push them down the stairs.

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